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efivars: only check for duplicates on the registered list
variable_is_present() accesses '__efivars' directly, but when called via gsmi_init() Michel reports observing the following crash, BUG: unable to handle kernel NULL pointer dereference at (null) IP: variable_is_present+0x55/0x170 Call Trace: register_efivars+0x106/0x370 gsmi_init+0x2ad/0x3da do_one_initcall+0x3f/0x170 The reason for the crash is that '__efivars' hasn't been initialised nor has it been registered with register_efivars() by the time the google EFI SMI driver runs. The gsmi code uses its own struct efivars, and therefore, a different variable list. Fix the above crash by passing the registered struct efivars to variable_is_present(), so that we traverse the correct list. Reported-by: Michel Lespinasse <walken@google.com> Tested-by: Michel Lespinasse <walken@google.com> Cc: Mike Waychison <mikew@google.com> Cc: Matthew Garrett <matthew.garrett@nebula.com> Cc: Seiji Aguchi <seiji.aguchi@hds.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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37b7f3c765
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1 changed files with 7 additions and 5 deletions
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@ -1628,10 +1628,11 @@ static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
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return count;
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}
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static bool variable_is_present(efi_char16_t *variable_name, efi_guid_t *vendor)
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static bool variable_is_present(struct efivars *efivars,
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efi_char16_t *variable_name,
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efi_guid_t *vendor)
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{
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struct efivar_entry *entry, *n;
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struct efivars *efivars = &__efivars;
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unsigned long strsize1, strsize2;
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bool found = false;
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@ -1703,8 +1704,8 @@ static void efivar_update_sysfs_entries(struct work_struct *work)
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if (status != EFI_SUCCESS) {
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break;
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} else {
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if (!variable_is_present(variable_name,
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&vendor)) {
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if (!variable_is_present(efivars,
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variable_name, &vendor)) {
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found = true;
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break;
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}
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@ -2008,7 +2009,8 @@ int register_efivars(struct efivars *efivars,
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* we'll ever see a different variable name,
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* and may end up looping here forever.
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*/
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if (variable_is_present(variable_name, &vendor_guid)) {
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if (variable_is_present(efivars, variable_name,
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&vendor_guid)) {
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dup_variable_bug(variable_name, &vendor_guid,
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variable_name_size);
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status = EFI_NOT_FOUND;
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